fs: dlm: fix DLM_IFL_CB_PENDING gets overwritten
This patch introduce a new internal flag per lkb value to handle internal flags which are handled not on wire. The current lkb internal flags stored as lkb->lkb_flags are split in upper and lower bits, the lower bits are used to share internal flags over wire for other cluster wide lkb copies on other nodes. In commit 61bed0ba ("fs: dlm: use a non-static queue for callbacks") we introduced a new internal flag for pending callbacks for the dlm callback queue. This flag is protected by the lkb->lkb_cb_lock lock. This patch overlooked that on dlm receive path and the mentioned upper and lower bits, that dlm will read the flags, mask it and write it back. As example receive_flags() in fs/dlm/lock.c. This flag manipulation is not done atomically and is not protected by lkb->lkb_cb_lock. This has unknown side effects of the current callback handling. In future we should move to set/clear/test bit functionality and avoid read, mask and writing back flag values. In later patches we will move the upper parts to the new introduced internal lkb flags which are not shared between other cluster nodes to the new non shared internal flag field to avoid similar issues. Cc: stable@vger.kernel.org Fixes: 61bed0ba ("fs: dlm: use a non-static queue for callbacks") Reported-by:Bob Peterson <rpeterso@redhat.com> Signed-off-by:
Alexander Aring <aahringo@redhat.com> Signed-off-by:
David Teigland <teigland@redhat.com>
parent
fe15c26e
Please register or sign in to comment